Bicycle Test Research Articles

PULSE ARRIVAL TIME CAN TRACK CHANGES IN SYSTOLIC BLOOD PRESSURE

Objective: Automated cuff-based blood pressure (BP) monitoring is limited to intermittent measurements vulnerable to movement. Pulse arrival time (PAT), calculated using electrocardiography (ECG) and photo plethysmography (PPG), has shown promise for non-invasive, continuous BP monitoring. The precise relationship between BP parameters and PAT under varying conditions remains to be fully understood. This study aimed to investigate the correlation between PAT and BP under different exercise modalities. Design and method: Data was analyzed on 33 volunteers aged 18 years or older with and without hypertension. The test protocol consisted of isometric leg exercise, an incremental ergometer bicycle test and seated periods of rest before, in-between and after. PAT was measured with an easy-to-use chest belt consisting of a 1-channel ECG and PPG sensor. PAT was calculated and averaged using a gliding average over 200 cycles from the R-wave in the ECG signal to the foot of the PPG waveform. Reference BP was measured every minute manually with an aneroid sphygmomanometer. Systolic- and diastolic BP was recorded to the nearest second for optimal synchronicity. Results: Subjects were aged 42.3 ± 13.3 years, ranging from 18–70. 48.5% were males, 18.2% had a prior diagnosis of hypertension and 15.2 % used antihypertensive medication. Systolic- and diastolic BP at inclusion were 123.6 ± 16.1 and 76.4 ± 8.4 mmHg with ranges from 98–168 and 66–100 mmHg respectively. Pearson's correlation between systolic BP and PAT was -0.86 ± 0.08, -0.84 ± 0.14 and -0.81 ± 0.14 for the full protocol, isometric exercise and dynamic exercise respectively. Corresponding correlation for diastolic BP was 0.43 ± 0.31, -0.75 ± 0.20 and 0.39 ± 0.35. For diastolic BP, correlation with PAT was positive in most subjects for the full protocol (94%) and dynamic exercise (79%), and negative in all subjects for isometric exercise. Systolic BP showed negative correlation inn all subjects for all analyses. Figure 1 shows test protocol and results for one subject. Conclusions: The results suggest that pulse arrival time can track changes in systolic blood pressure. The relationships between diastolic blood pressure and pulse arrival time varied between exercise modalities and remains to be further elucidated.

Lifestyle exercise attenuates immunosenescence; flow cytometry analysis

BackgroundInteraction of physical activity and overall immune profile is very complex and depends on the intensity, duration and frequency of undertaken physical activity, the exposure to cytomegalovirus (CMV) infection and the age-related changes in the immune system. Daily physical activity, which particularly influences immunity, declines dramatically with age. Therefore, the aim of the study was to explain whether physical activity sustained throughout life can attenuate or reverse immunosenescence.MethodsNinety-nine older adults (60–90 years) were recruited for the study. According to the 6-min walk test (6WMT), the Åstrand-Ryhming bike test (VO2max) and Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire, the individuals were classified as physically active (n = 34) and inactive (n = 20) groups. The analysis of T lymphocytes between active vs. inactive participants was performed using eight-parameter flow cytometry.ResultsAnalysis of the baseline peripheral naïve and memory T lymphocytes showed a significant relationship of lifestyle exercise with the CD4/CD8 ratio. Above 50% of physically active participants demonstrated the CD4/CD8 ratio ≥ 1 or ≤ 2.5 contrary to the inactive group who showed the ratio < 1. The older adults with the result of 6WMT > 1.3 m/s and VO2max > 35 mL/kg/min had a significantly higher CD4+CD45RA+ T lymphocyte percentage and also a higher ratio of CD4+CD45RA+/CD4+CD45RO+. Interestingly, in active older adults with IgG CMV+ (n = 30) the count of CD4+CD45RA+ T lymphocytes was higher than in the inactive group with IgG CMV+ (n = 20).ConclusionBased on the flow cytometry analysis, we concluded that lifestyle exercise could lead to rejuvenation of the immune system by increasing the percentage of naïve T lymphocytes or by reducing the tendency of the inverse CD4/CD8 ratio.

Fitness, Fatness, and Mortality in Men and Women From the UK Biobank: Prospective Cohort Study.

BackgroundCardiorespiratory fitness may moderate the association between obesity and all‐cause mortality (ie, the “fat‐but‐fit” hypothesis), but unaddressed sources of bias are a concern.Methods and ResultsCardiorespiratory fitness was estimated as watts per kilogram from a submaximal bicycle test in 77 169 men and women from the UK Biobank cohort and combined with World Health Organization standard body mass index categories, yielding 9 unique fitness‐fatness combinations. We also formed fitness‐fatness combinations based on bioimpedance as a direct measure of body composition. All‐cause mortality was ascertained from death registries. Multivariable‐adjusted Cox regression models were used to estimate hazard ratios and 95% CIs. We examined the association between fitness‐fatness combinations and all‐cause mortality in models with progressively more conservative approaches for accounting for reverse causation, misclassification of body composition, and confounding. Over a median follow‐up of 7.7 years, 1731 participants died. In our base model, unfit men and women had higher risk of premature mortality irrespective of levels of adiposity, compared with the normal weight–fit reference. This pattern was attenuated but maintained with more conservative approaches in men, but not in women. In analysis stratified by sex and excluding individuals with prevalent major chronic disease and short follow‐up and using direct measures of body composition, mortality risk was 1.78 (95% CI, 1.17–2.71) times higher in unfit‐obese men but not higher in obese‐fit men (0.94 [95% CI, 0.60–1.48]). In contrast, there was no increased risk in obese‐unfit women (1.09 [95% CI, 0.44–1.05]) as compared with the reference.ConclusionsCardiorespiratory fitness modified the association between obesity and mortality in men, but this pattern appeared susceptible to biases in women.

Comparison of aerobic profiles between the field-based 20 m-shuttle run test and the laboratory-based bike ergometer test in runners

Comparison of aerobic profiles between the field-based 20 m-shuttle run test and the laboratory-based bike ergometer test in runners

Psychometrics, interpretation and clinical implications of hierarchical models of psychopathology.

Psychometrics, interpretation and clinical implications of hierarchical models of psychopathology.

Impaired coronary flow velocity reserve is associated with cardiovascular risk factors but not with angina symptoms

ObjectivesCoronary microvascular dysfunction (CMD) is considered to cause angina pectoris in a large proportion of women with no obstructive coronary artery disease (CAD). However, data supporting a relation between angina...

Influence of exertional hypoxemia on cerebral oxygenation in fibrotic interstitial lung disease

It is unknown whether hypoxemia, a hallmark of fibrotic interstitial lung disease (f-ILD), may impair cerebral oxygenation during exercise in these patients.Twenty-seven patients [23 males, 72 ± 8 years, lung diffusing capacity for carbon monoxide (DLCO) = 44 ± 11 % predicted] and 12 controls performed an incremental bicycle test. Prefrontal oxygenation [tissue saturation index (TSI)] was assessed by near-infrared spectroscopy.Patients showed lower arterial O2 saturation (SpO2) and larger fall in cerebral TSI during exercise vs controls (p < 0.05). However, changes (Δ) from rest to peak-exercise in SpO2 (-2.2 % to -26.9 %) and TSI (1.4 % to -16.6 %) varied substantially among patients. In the 16 patients showing significant cerebral deoxygenation (Δ TSI ≥ 4% based on controls), SpO2 decreased more (-12.6 ± 6.7 % vs -5.7 ± 2.8 %, p = 0.001) and peak O2 uptake was lower (68.3 ± 19.2 % vs 87.8 ± 24.8 % predicted, p = 0.03) vs their 11 counterparts. In association with DLCO and forced vital capacity, Δ cerebral TSI independently predicted peak O2 uptake on multivariable regression analysis (R2 = 0.54).Exertional hypoxemia impairs cerebral oxygenation in a dose-dependent fashion in f-ILD. Future studies are warranted to investigate whether this potentially reversible abnormality play a contributory role in limiting exercise tolerance in these patients.

Discriminating performance profiles of cycling disciplines

The aim of this study was to document the athletic profiles of adolescent and young adult high performance cycling athletes and to investigate to what extent different cycling disciplines can be discriminated from each other based on a generic test battery. A total of 243 adolescent (12.0- 15.99 y) and 63 young adult (&gt;=16 y) male cyclists from road cycling, track cycling, cyclo-cross, and mountain bike (MTB) participated in the study. All participants performed four anthropometric, five physical, three motor coordination, and two cycling-specific tests. Using discriminant analyses, the young adult athletes could be correctly classified to their discipline for 80.7%. Track cyclists outperformed the other disciplines in explosive and coordinative skills while for cyclo-cross, and particularly MTB, the performance on the shuttle bike test seemed to be a distinctive variable. Road cyclists however, showed a significant overlap in performance characteristics with the other disciplines. In spite of the less pronounced discriminative character in the adolescent cycling population (51.0%), the discriminative characteristics are in line with the results of the young adults. This study allows to orient cyclists towards their best-fitted discipline in young adulthood. The relevance of these findings for coaches, experts and federations with respect to early/late specialization, and talent orientation are discussed.

Sex-differences In Exercising Hemodynamics: Role Of Exercising Muscle Mass

Sex-differences in O2 transport include O2 content (CaO2) and quantity of muscle mass. PURPOSE: To determine their consequences on exercising hemodynamics with large (e.g., 2-leg cycling (BIKE)) vs. small (e.g., 1-leg knee extension (KE)) muscle mass. METHODS: Healthy young subjects (4M, 3W) completed BIKE and KE exercise tests. The femoral artery and vein were catheterized to measure leg blood flow (Q), CaO2, and mean arterial pressure (MAP). Vascular conductance (VC), O2 delivery, and leg O2 uptake (VO2) were calculated. Measures were normalized to the right leg (BIKE) or quadriceps (KE) lean mass. Whole body VO2 was measured with a metabolic cart. Men and women were compared at similar and maximal work rates. RESULTS: Body mass was greater in men (M: 80±6 vs. W: 59±12 kg, p=0.03). Although quadriceps mass (3.3±0.2 vs. 2.0±0.3 kg, p<0.001) and CaO2 were lower, women had a higher mass-specific Q, VC (p=0.054), O2 delivery, and leg VO2 to maintain whole body VO2 during similar KE (Table 1). These differences were maintained during maximal KE, at which women tended to achieve a higher mass-specific work rate (21±2 vs. 25±3 W·kg-1, p=0.10). They were also apparent during similar BIKE despite a lower leg lean mass in women (8.7±0.3 vs. 5.3±0.7 kg, p<0.001). However, the differences were no longer present during maximal BIKE when mass-specific work rate was similar (21±2 vs. 20±2 W·kg-1, p=0.70) and whole body VO2 was lower in women. CONCLUSION: These findings highlight a greater hemodynamic capacity for women to overcome differences in CaO2 and maintain whole body VO2 at similar work rates during exercise. They also implicate the quantity of exercising muscle in facilitating the greater hemodynamic capacity and mass-specific work rate during maximal exercise with a small but not large muscle mass. Support: The Swedish National Centre for Research in Sports, Ministerio de Educacion y Ciencia of Spain, Dr. Manuel Morales Foundation, NSERCTable 1: Exercising hemodynamics (*p<0.05, **p<0.01, ***p<0.001 men vs. women)

Comparison Of The Wingate Anaerobic Test And The New Power Bike Test On Anaerobic Power

Anaerobic power (AP) is the one of the most important factors influencing athletic performance in many sports. Although the Wingate anaerobic test (WAT) has been the most representative measurement for assessing AP, exhaustive testing procedure limits its use in the lab. Recently, the New Power Bike test (NPT) was developed and can measure anaerobic power with maximal pedaling for only four seconds without load. PURPOSE: The purpose of this study was to 1) compare the power output between the WAT and the NPT and 2) examine relationships among WAT, NPT, and vertical jump test (VJT). METHODS: Thirty-seven participants (age, 26.65±4.16 years; height, 169.2±9.56 cm; weight, 84.49±20.10 kg) went through AP measurements using the WAT, NPT, and VJT. The participant conducted VJT and either WAT or NPT randomly on the first visit. Participants then performed either WAT or NPT via a counterbalanced design on second visit with one-week interval. The Pearson correlation coefficient were computed among the WAT, NPT, and VJT scores and the effect size was evaluated with Cohen’s d. Variance between the variables was calculated with the coefficient of determination (r2). The statistical significance was set at 0.05. RESULTS: There were significant positive correlations between the WAT and NPT in the mean of peak power (MPP) (r = 0.727, p <0.001) and mean of relative peak power (MRPP) (r = 0.388, p = 0.018), respectively. The MPP (976.18±344.17 W) and MRPP (11.47±2.60 W/kg) of the NPT were significantly higher than the MPP (705.67±249.30 W) and MRPP (8.34±2.55 W/kg) of WAT. There were positive correlations in MPP between NPT and VJT (r = 0.620, p < 0.001) between the WAT and VJT (r = 0.399, p = 0.015). Also, there were significant correlation (r(35) = .25, p =.014, d = 5.1) in MRPP between WAT and VJT, with shared variance between the variables at 0.6%. CONCLUSION: There were significant positive correlations between the WAT and NPT in MPP and MRPP. The NPT also showed greater correlation with field test (VJT). So, the NPT can be a good alternative measurement with lesser efforts for assessing anaerobic power and predict athletic performance in the field.

The Effect of Water Exercise Therapy Given to Patients With Rheumatoid Arthritis

It is well known that patients suffering from rheumatoid arthritis have a reduced muscular function. The positive effect of physical training on rheumatic patients has been shown. In this study the effect of exercise therapy performed in a heated swimming pool has been evaluated for eight patients in a non-acute stage of rheumatoid arthritis. The median pre-treatment maximal isometric and isokinetic quadriceps strength was 88 Nm (44-146) and 99 Nm (62-149) respectively, which was 61% and 70% of that found in a control group of healthy persons. After 2 months exercise therapy the median maximal isometric and isokinetic quadriceps strength increased by 38% and 16% compared to the pre-treatment value (p less than 0.02 and p less than 0.05). All patients, except one who developed cardiac arrhythmia during the second test, accomplished a submaximal bicycle test (a.m. Astrand). An increase in the aerobic capacity was observed in all patients after the training period.

686-P: Exercise Alone and in Combination with Liraglutide Exert Clinically Relevant Improvements in Cardiorespiratory Fitness during 1-Year Weight Loss Maintenance: The S-LITE Randomized Trial

Introduction: Improved cardiorespiratory fitness (CRF) is associated with reduced mortality. Each metabolic equivalent (MET) increase in CRF is associated with 10-25 % improvements in survival. The aim was to explore changes in fitness during weight maintenance with the glucagon-like peptide-1 receptor agonist liraglutide and/or exercise. Methods: Women and men with obesity (18-65 years, BMI 32-43 kg/m2) who achieved ≥ 5 % weight loss during an 8-week very low-calorie diet (VLCD) were randomized to (1) liraglutide 3 mg/day (LIRA), (2) exercise 150 min/week + placebo (EX), (3) exercise 150 min/week + liraglutide 3 mg/day (LIRA+EX), or (4) placebo (PLA) for one year. CRF was measured as peak oxygen consumption using indirect calorimetry during an incremental bicycle test. Physical functioning was evaluated as time to ascend/descend an 11-step stairway twice. Results: A total of 215 participants were included. Changes in fitness after VLCD and 1-year weight maintenance program are presented in Table 1. Conclusion: Exercise alone and in combination with liraglutide exert clinically relevant improvements in cardiorespiratory fitness and improve physical functioning. Thus, adding liraglutide does not interfere with the ability to improve fitness with exercise, supporting the combined use in weight maintenance. Disclosure S. Jensen: None. C. Janus: Research Support; Spouse/Partner; Mercodia, Novo Nordisk A/S. Research Support; Self; Novo Nordisk Foundation. Research Support; Spouse/Partner; Novo Nordisk Foundation. Speaker’s Bureau; Spouse/Partner; Merck Sharp &amp;lt; Dohme Corp. J.R. Lundgren: None. C.R. Juhl: None. M.B. Blond: None. B. Stallknecht: None. J.J. Holst: Advisory Panel; Self; AstraZeneca, Merck Sharp &amp;lt; Dohme Corp., Novo Nordisk A/S, Zealand Pharma A/S. Other Relationship; Spouse/Partner; Antag Therapeutics. S. Madsbad: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Merck Sharp &amp;lt; Dohme Corp., Novo Nordisk A/S, Sanofi-Aventis. Research Support; Self; Boehringer Ingelheim International GmbH, Novo Nordisk A/S. Speaker’s Bureau; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Novo Nordisk A/S. S.S. Torekov: Research Support; Self; Novo Nordisk Inc. Funding Novo Nordisk Foundation (NNF16OC0019968, NNF15SA0018486); University of Copenhagen; Helsefonden; Danish Diabetes Academy

Exercise Field Testing in Children: A New Approach for Age-Appropriate Evaluation of Cardiopulmonary Function

Based on the wide range of problems to effectively perform cardiopulmonary testing in young children, this study strives to develop a new cardiopulmonary exercise test for children using a mobile testing device worn in a backpack in order to test children during their natural movement habits, namely, running outdoors. A standard cardiopulmonary exercise ramp test on a cycle ergometer was performed by a group of twenty 7–10-year-old children. The results were compared with a self-paced incremental running test performed using a mobile cardiopulmonary exercise measuring device in an outdoor park. The children were able to reach significantly higher values for most of the cardiopulmonary exercise variables during the outdoor test and higher. Whereas a plateau in {dot{text{V}}text{O}}_{{2}} was reached by 25% of the children during the outdoor test, only 75% were able to reach a reasonable VT2, let alone {dot{text{V}}text{O}}_{{{text{2peak}}}}, during the bicycle test. The heart rate at VT1, the O2-pulse, and the OUES were comparable between both tests. OUES was also positively correlated with {dot{text{V}}text{O}}_{{{text{2peak}}}} in both tests. Testing children outdoors using a mobile cardiopulmonary exercise unit represents an alternative to standard exercise testing, but without the added problems of exercise equipment like treadmills or bicycles. It allows for individualized exercise testing with the aim of standardized testing durations instead of standardized testing protocols. The running speeds determined during the outdoor tests may then be used to develop age-adapted testing protocols for treadmill testing.

Prognostic Relevance of Cardiorespiratory Fitness as Assessed by Submaximal Exercise Testing for All-Cause Mortality: A UK Biobank Prospective Study

ObjectiveTo investigate whether the inverse associations of cardiorespiratory fitness (CRF) with all-cause and cardiovascular mortality in the general population vary among individuals who are at different levels of pretest risk. Patients and MethodsCardiorespiratory fitness was assessed through submaximal bicycle tests in 58,892 participants aged 40 to 69 years who completed baseline questionnaires between January 1, 2006, and December 31, 2010, in the UK Biobank Prospective Study. Participants were categorized into risk categories, which determined allocation to an individualized bicycle protocol. The groups at minimal risk (category 1), small risk (category 2), and medium risk (category 3) were tested at 50%, 35% of the predicted maximal workload, and constant level, respectively. We investigated associations of CRF with mortality across different levels of pretest risk and determined whether CRF improves risk prediction. ResultsDuring a median follow-up of 5.8 years, 936 deaths occurred. Cardiorespiratory fitness was linearly associated with mortality risk. Comparing extreme fifths of CRF, the multivariable-adjusted hazard ratios (95% CIs) for mortality were 0.63 (0.52-0.77), 0.54 (0.36-0.82), 0.81 (0.46-1.43), and 0.58 (0.48-0.69) in categories 1, 2, and 3 and overall population, respectively. The addition of CRF to a 5-year mortality risk score containing established risk factors was associated with a C-index change (0.0012; P=.49), integrated discrimination improvement (0.0005; P<.001), net reclassification improvement (+0.0361; P=.005), and improved goodness of fit (likelihood ratio test, P<.001). Differences in 5-year survival were more pronounced across levels of age, smoking status, and sex. ConclusionCardiorespiratory fitness, assessed by submaximal exercise testing, improves mortality risk prediction beyond conventional risk factors and its prognostic relevance varies across cardiovascular risk levels.

Exercise capacity, physical activity, and health-related quality of life in adults with CHD.

The aim of this study was to assess exercise capacity, physical activity, and health-related quality of life within a broad and unselected group of adults with CHD. From April 2009 to February 2014, 1310 patients were assessed for suitability to participate in this single-centre cross-sectional study. Seven hundred and forty-seven (57%) patients were included, performed a submaximal bicycle test, and answered questionnaires regarding physical activity and health-related quality of life. Exercise capacity, physical activity, and health-related quality of life were compared with reference values and correlations were studied. The exercise capacities of men and women with CHD were 58.7 and 66.3%, respectively, of reference values. Approximately, 20-25% of the patients did not achieve the recommended amount of physical activity. In addition, men scored significantly less points on 7 out of 10 scales of health-related quality of life and women in 6 out of 10 scales, compared with reference values. The strongest correlation was between exercise capacity and the Short Form-36 (physical function). Exercise capacity was impaired in all adults with CHD, including those with less complicated CHD. One-quarter of the patients did not achieve the recommended levels of physical activity. Exercise tests followed by individualised exercise prescriptions may be offered to all patients with CHD aiming to increase exercise capacity, levels of physical activity, improve health-related quality of life, and reduce the risk of acquired life-style diseases.

Reference values and secular trends for cardiorespiratory fitness in children and adolescents with obesity.

To present specific reference values for cardiorespiratory fitness (CRF) in children with obesity and to analyse secular trends of CRF in the studied population. Cardiorespiratory fitness, the maximal oxygen uptake (VO2 max), was estimated with the Åstrand-Rhyming submaximal bicycle test, in 705 Swedish children (356 girls, 8-20years) with obesity according to the International Obesity Task Force (IOTF). Data were collected from 1999 to 2013. Secular trends, analysed with multiple linear regression, were adjusted for age, height and body mass index standard deviation score (BMI SDS). All children had low CRF compared with normal weight standards but there was a marked variability of CRF in children with obesity, which was possible to quantify with the developed obesity specific CRF reference values. The mean value of absolute VO2 max (L/min) increased with age and relative VO2 max (mL/kg/min) decreased with age in both boys and girls. There was a negative secular trend in both sexes (P<.001). These are the first obesity specific reference values of CRF in children enabling clinical evaluation in childhood obesity treatment. Cardiorespiratory fitness in children with obesity has declined the last decades, indicating that also within this vulnerable group physical activity has gone down.

Exercise and myocardial injury in hypertrophic cardiomyopathy

ObjectiveTroponin and high signal intensity on T2-weighted (HighT2) cardiovascular magnetic resonance imaging (CMRi) are both markers of myocardial injury in hypertrophic cardiomyopathy (HCM). The interplay between exercise and disease development...

Cardiopulmonary Capacity in Children During Exercise Testing: The Differences Between Treadmill and Upright and Supine Cycle Ergometry.

Background/Hypothesis: Cardiopulmonary exercise testing (CPET) is used in the assessment of function and prognosis of cardiopulmonary health in children with cardiac and pulmonary diseases. Techniques, such as cardiac MRi, and PET-scan, can be performed simultaneously with exercise testing. Thus, it is desirable to have a broader knowledge about children’s normal cardiopulmonary function in different body postures and exercise modalities. The aim of this study was to investigate the effect of different body positions on cardiopulmonary function in healthy subjects performing CPETs.Materials and Methods: Thirty-one healthy children aged 9, 12, and 15 years did four CPETs: one treadmill test with a modified Bruce protocol and three different bicycle tests with different body postures, sitting, tilted 45°, and lying flat (0°). For the bicycle tests, a 20-watt ramp protocol with a pedal frequency of 60 ± 5 rotations per minute was used. Continous ECG and breath-by-breath measurements was done throughout the tests. Cardiac structure and function including aortic diameter were evaluated by transthoracic echocardiography prior to the tests. Doppler measurements of the blood velocity in the ascending aorta were measured prior to and during the test. Prior to every test, the participants performed pulmonary function tests with maximum voluntary ventilation test.Results: There is a significantly (p < 0.05) lower peak in all bicycle tests compared with the treadmill test. There is lower corrected peak (ml kg−0.67 min−1), but not relative peak (ml kg−1 min−1), in the supine compared with the upright bicycle test. There are no differences in peak stroke volume or cardiac output between the bicycle modalities when calculated from aortic blood flow. Peak heart rate decreases from both treadmill to upright bicycle and from upright bicycle to the supine test (0°).Conclusion: There are no differences in peak cardiac output between the upright bicycle test and supine bicycle tests. Heart rate and corrected peak are lower in the supine test (0°) than the upright bicycle test. In the treadmill test, it is a higher absolute and relative peak . Despite the latter differences, we are convinced that both upright and supine bicycle tests are apt in the clinical setting when needed.

A new maximal bicycle test using a prediction algorithm developed from four large COPD studies

ABSTRACT Background: Maximum exercise workload (WMAX) is today assessed as the first part of Cardiopulmonary Exercise testing. The WMAX test exposes patients with COPD, often having cardiovascular comorbidity, to risks. Our research project was initiated with the final aim to eliminate the WMAX test and replace this test with a predicted value of WMAX, based on a prediction algorithm of WMAX derived from multicentre studies. Methods: Baseline data (WMAX, demography, lung function parameters) from 850 COPD patients from four multicentre studies were collected and standardized. A prediction algorithm was prepared using Random Forest modelling. Predicted values of WMAX were used in a new WMAX test, which used a linear increase in order to reach the predicted WMAX within 8 min. The new WMAX test was compared with the standard stepwise WMAX test in a pilot study including 15 patients with mild/moderate COPD. Results: The best prediction algorithm of WMAX included age, sex, height, weight, and six lung function parameters. FEV1 and DLCO were the most important predictors. The new WMAX test had a better correlation (R2 = 0.84) between predicted and measured WMAX than the standard WMAX test (R2 = 0.66), with slopes of 0.50 and 0.46, respectively. The results from the new WMAX test and the standard WMAX test correlated well. Conclusion: A prediction algorithm based on data from four large multicentre studies was used in a new WMAX test. The prediction algorithm provided reliable values of predicted WMAX. In comparison with the standard WMAX test, the new WMAX test provided similar overall results.

Exergy efficiency on incremental stationary bicycle test: A new indicator of exercise performance?

The first and second laws of the thermodynamics were applied to the human body to evaluate the performance of subjects under different training levels. Ten cyclists were evaluated in the stationary bicycle with the indirect calorimetry analysis to obtain the metabolism on an energy and exergy basis. A distinguishing feature of this article is the evaluation of the exergy efficiency of the body with the knowledge of the real performed power and the internal temperature (measured tympanic temperature and calculated esophagus temperature). Regarding the skin temperature, an infrared camera was used to measure different parts of the body. Therefore, the phenomenological behavior of the body was assessed and used as a basis to apply the exergy analysis. Results indicate that the destroyed exergy can be an indicator of performance when compared with maximum oxygen consumption. Nevertheless, more experiments must be carried out to proper state if there is a correlation. Eventually, the exergy efficiency was calculated for all subjects, and its value was around 23 to 28%.